1. Field of the Invention
The present invention relates to a data communication method and system for a mobile communication network. More particularly, the present invention relates to a mobile communication network using an improved medium access control mechanism that is capable of improving Quality of Service (QoS) and power control efficiency while maintaining advantages of channelization effects.
2. Description of the Related Art
Typically, wireless network environment is characterized by an often noisy and shared signal propagation medium. In order to provide fair scheduling to a plurality of network nodes and guarantee reliable data transmissions, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) Medium Access Control (MAC) protocol has been adopted in wireless networks.
Wireless MAC protocols are designed such that a plurality of nodes participate in channel contention, and a node transmission privilege acquired through the contention transmits a frame successfully.
MAC protocols can be classified into either a contention-based or a reservation-based approach.
Typically, contention-based MAC protocols are implemented with the aforementioned CSMA/CA scheme. With its simple structure and channel utilization efficiency, the CSMA/CA-based MAC protocols are widely employed in wireless networks. However, the CSMA/CA-based MAC protocols are difficult to control a Quality of Service (QoS). Since the transmission time of a sender is not predictive of subsequent transmission times, the receiver should always stay in a standby, resulting in low power efficiency.
In contrast, the reservation-based MAC protocols are implemented with a Time Division multiple Access (TDMA) scheme. The TDMA-based MAC protocols allocate timeslots to the network nodes such that the packet delivery times of the networks are predictive. The receiver receives frames through the timeslot allocated to it and enters sleep mode during the other timeslots duration, thereby reducing power consumption and facilitating control of QoS. However, the reservation-based MAC protocol suffers from a low channel utilization efficiency.
Accordingly, there has been a long-felt need for an enhanced wireless MAC protocol and communication that is capable of improving QoS and power control while maintaining the channel utilization efficiency.